The Covenant are a group of aliens that play the roles of antagonist all through Halo: Combat Evolved. However, in Halo two, the smash hit sequal, You'll play the role of the Arbiter, an Elite. However, the only enemies you could kill as the Elite were heritic Covenant and the Flood. The roles of the covenant stand in hierarchy order
Prophets, graceful creatures that consider themselves the greatest of all Covenant. Brutes, As of Halo 2, brutes are the prophet's trusted guards. Elites, the commanders of all other covenant, Elites have four mandibles each lined with a row of teeth. Hunters, the living tanks of the covenant, having a fuel rod cannon on the right arm. Drones, the flying army man, their environment is preferably space, they hate atmospheric flight. Jackals, the bird like creatures hiding behind an energy field, and grunts, as they are: grunts. thier main purpose is to serve the higher classes. unmentioned races are Engineers, and Sharaquoi, these beasts are mentioned in Conversations of the universe, located in the Halo 2 collector's addition.

the Covenant is a basically a group of Aliens bonded together under 1 religion. Like the previous person mentioned, it consists of the Grunts, the Jackals, The Elites, the Hunters, The Brutes, the Drones, the engineers, and the Prophets. The Covenant have gathered most of their ranks through force, either the race joined them, or the plasma bombarded the hell out of the planet.

A collection of alien races consisting of Grunts, Jackals, Hunters, Elites, Brutes, Drones and Prophets. Humanity was not consumed by the Covenant and is therefore an enemy of the Covenant. Humanity's saviour, an augmented human (Spartan) named 'Master Chief' is the Human's last hope against those Covie Bastards.